A radar of this type used for tracking and for angular-deviation measurement, i.e. determining the offset in the position of the target with respect to the boresight axis of the antenna, presents a radiation pattern with linear polarization which is perpendicular to the direction of polarization of the wave emitted by the source illuminating the antenna. Since the skin echo reflected by the target, just like the signal sent by a jammer with which the target may be equipped, may have any direction of polarization whatever, the tracking radar can no longer accurately perceive the target. This is particularly true when the direction of polarization of the signal received is close to the normal operating polarization of the antenna, as may be the case with a rotating rectilinear polarization jammer.